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ব্যাখ্যা ও সঠিক সমাধান
উত্তর:
10
Lets say, Noman's age was five times of Shamim's age X years ago and their present ages are N and S respectivety.
So, N = 3S = 3×20 = 60 years.
Now, five years ago,
N - X = 5(S - X)
or, 60 - X = 5(20 - X)
or, 60 - X = 100 - 5X
or, 5X - X = 100 - 60
or, 4X = 40
or, X = 10 years